1. Field of the Invention
The present invention relates to a light guide plate, in particular to a light guide with a plurality of resembling triangular prisms.
The present invention provides a resembling prismatic structure of light guide plate to solve the waste of energy of light and creates emitting light from the non-uniform, selected, multiple and specific positions. The beams of the emitting light can also be focused to a special direction pointing to the opening of LCD substrate by the controlled, multiple and parallel entering light. The present invention simplifies the multifarious structures of the prior LCD backlight modules.
2. Disciption of Related Art
In generally, the backlight module comprises the light guide plate, the diffusion film and reflection film. In order to get the uniformly emitting light, the prior LCD backlight modules use the films having optical effects. These films include the prismatic film, the diffusion film, the reflection film and . . . etc. The energy of light was lost in the processes of repeating refraction and reflection between these films and wasted in the irradiation of the light irradiated the un-translucent part of the LCD.
As illustrated in U.S. Pat. No. 5,917,664, while it is formed by prism arrays, its aim is to avoid sudden change of brightness when across certain angle during changing viewing-angle.
Further, as shown in FIGS. 9a and 9b, “light guide plate having multi-focused reflecting patterns” of TAIWAN PATENT published No. 463957 has a plurality of multi-focused reflecting patterns on opposite face of emitting face of light guide plate. Each pattern has a round surface at center, with a plurality of annular round surfaces being concentric from said round surface. Incident light is reflected, by each pattern on light guide plate, upwards to form plane-type light source. This prior art is that brightness of plane-type light source is made evenly distributed by multi-directioned reflection of multi-focused reflecting mirrors.
The prior arts of backlight module mainly focus on emitting light evenly; As shown in U.S. Pat. No. 6,356,391, however it is formed by prism arrays also, its aim is to get light emitting of continuous and entire evenness.
As illustrated in FIGS. 10a and 10b, “plane-type light source” of TAIWAN PATENT published No. 538285 utilizes multi-direction refraction of concave lenses 11n or convex lenses11p so that the emitting face near lateral incident face has enough brightness.
As illustrated in FIGS. 11a, 11b, 12a and 12b, this prior art also has variant distribution concentration of concave mirrors12p or convex mirrors12n on opposite face of emitting face of light guide plate and lateral faces except incident face.
By the way of multi-direction of concave and convex mirrors' reflection and higher concentration of reflecting mirrors in periphery of light guide plate h where brightness is apt to be insufficient, it is possible to achieve evenness of brightness and direction of emitting of plane-type light source. The technological thought of the present invention is distinct from this prior art.
As illustrated in FIG. 13, “LCD having localized-light-transmitting backlight” of TAIWAN PATENT published No. 560621 has a plurality of light passages52 in reflecting layer51 on the bottom of LCD f, and has a micro-prisms-arrayed optical film g possessing light-focusing portions61 corresponding to light passages52, between LCD f and light guide plate h. The artificial light L5, after being concentrated, transmits through light passages52 in reflecting layer51, and into LCD f. The total output comes from combined effects of highly reflected natural light L4 from reflecting layer51 and artificial light L5 enhanced by micro-prism-arrayed optical film g, with enhanced total light output of LCD.
The stronger function of light-focusing portions61, the more artificial light L5 transmitting through light passages52, and the less proportion of area occupied by light passages52, and therefore the larger proportion of area used to reflect, and then more reflected natural light L4 can be used. According to this design, light output of LCD f can be promoted, and contrast of LCD f to natural light L4 can be increased.
This prior art is characterized in reflecting layer51 possessing light passages52 and micro-prisms-arrayed optical film g possessing light-focusing portions61.
Although it would make emitted artificial light L5 point to specified positions according to its claims' declaration, the critical structure of micro-prisms-arrayed optical film g possessing light-focusing portions61 and corresponding parameters thereof are not disclosed at all.
Most important of all, the present invention discloses not only its optical process, but also the microstructure, including its characteristics and its corresponding parameters.